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Characteristics And The Metallogenic Mechanism Of Fluid Inclusions In Layikeleke Porphyry Mo-Cu Deposit,Xinjiang Province

Posted on:2016-12-06Degree:MasterType:Thesis
Country:ChinaCandidate:J WuFull Text:PDF
GTID:2180330470983192Subject:Geological engineering
Abstract/Summary:PDF Full Text Request
Qiongheba area is an important ore concentration area of the circum~Junggar porphyritic copper deposit belts. Layikeleke porphyry copper deposit lies in the north~east of the Kasakhstan~Junggar plate, which is the latest discovered large porphyry deposit in the area. The ore body hosted in tonalite, and the wall rock is tuff of lower Devonian Tuoranggekuduke group, that the latest drilling showed wall rock also rich in mineralization. The ore~controlling factors of Layikeleke deposit are Lower Devonian strata, NW~trending structure and magmatic rocks. Mineralization is mainly related to phyllic and silicification alteration. The metallic minerals of Layikeleke deposit are relatively simple, mainly chalcopyrite and molybdenite, that in some drilling also develop sphalerite and gold mineralization. Through lithology and microscope observation, divided the main mineralization process into four stages, which include phyilic stage, molybdenite stage, chalcopyrite stage and late metallogenic stage.Petrographic observations to the fluid inclusion in quartz of the four stages indicate that the main types of fluid inclusion are aqueous inclusions and daughter~mineral~bearing multiphase inclusions. The phyllic stage is characterized by two different fluid inclusions, the first one is aqueous inclusions and the other one is daughter~mineral~bearing multiphase inclusions. Former have middle~high temperature and middle~low salinity, Th(homogenization temperature) is 230~560℃, and the peak is 250~400℃ with salinity of 2.07%~8.41%, density of 0.46~0.72 g/cm3, pressure of 21~35MPa. The latter Th(homogenization temperature) is 280~339℃ with salinity of 36.68%~41.49%, density of 0.64~0.74 g/cm3, pressure of 46~59MPa, which is middle temperature and middle-high salinity and the bubbles disappear first, then halite crystals melt. In this stage, aqueous inclusions and daughter~mineral~bearing multiphase inclusions coexist, indicate that fluid occurred immiscibility or boiling in the pressure range, resulted large numbers of sulfide percipitated. In molybdenite stage, the ore~forming fluid is characterized by middle temperature and middle~low salinity, Th(homogenization temperature) is 253~392℃ with salinity of 3.23%~8.14%, density of 0.48~0.97g/cm3, pressure of 92-36MPa. In chalcopyrite stage, the ore-forming fluid is characterized by middle~low temperature and middle~low salinity, Th(homogenization temperature) is 134~385℃ and the peak is 250~350℃ with salinity of 1.91%~6.16%, density of 0.64~0.94g/cm3, pressure of 10-27MPa. In late metallogenic stage, the ore-forming fluid is characterized by middle-low temperature, Th(homogenization temperature) is 175-365℃ and the peak is 200-300℃. The metallogenic pressure is approximately 46-59MPa, metallogenic depth is 4.7km-6km.The characteristics of hydrogen and oxygen isotope indicate that ore-forming fluid are mainly from the magmatic water and meteoric water. Meanwhile, according to the assemblage,propertiesand evolution characteristics of different fluid inclusions, the immiscibility and decrease of temperature and pressure are the main mechanisms for sulfide percipitated to mineralization. The migration direction of the fluid is from the western deep source to the east in the mine. The western mine is the most favorable metallogenic target.
Keywords/Search Tags:Layikeleke porphyry copper(molybdenum)deposit, Metallogenic stages, Fluid inclusion, Genesis of the deposit
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